1. Field of the Invention
The present invention generally relates to a method of fabricating devices on semiconductor substrates. More specifically, the invention relates to a method for removal of residue from a semiconductor substrate.
2. Description of the Related Art
Microelectronic devices are generally fabricated on a semiconductor substrate as integrated circuits wherein various metal layers are interconnected to one another to facilitate propagation of electrical signals within the device. One typical process used for fabrication of the microelectronic devices is a plasma etch process. During plasma etch processes, one or more layers that comprise a metal or a metal-based compound are removed, either partially or in total, to form a feature (e.g., interconnect line or contact via) of the integrated circuit.
Generally, plasma etch processes use gas chemistries that, when reacted with the material comprising the etched layer or etch mask, may produce non-volatile byproducts. Such by-products accumulate on the substrate as a residue. In the art, such residue is commonly called a “post-etch residue.” Post-etch residue may interfere with processing of the substrate, e.g., the residue may contaminate the remaining layers or cause difficulties in depositing subsequent layers. In addition, metal-containing residue may also cause short-circuits that disrupt or degrade operation of the integrated circuits.
Conventional methods for removing residue typically include multiple wet treatments of the substrate along with an intermediate plasma strip process using an oxygen-based chemistry. Multiple wet treatments, along with an intermediate plasma strip process (i.e., etch and strip processes), reduce productivity during fabrication of the microelectronic devices. Further, the oxygen-based plasma strip process may form hard to remove metal oxides on the substrate or otherwise corrode the substrate.
Therefore, there is a need in the art for an improved method for removing residue from a substrate during fabrication of microelectronic devices.